Prof. Dr. Thorsten Koch

koch@zib.de


Projects as a project leader

  • MI10

    Acyclic network flows

    Dr. Benjamin Hiller / Prof. Dr. Thorsten Koch / Prof. Dr. Martin Skutella

    Project heads: Dr. Benjamin Hiller / Prof. Dr. Thorsten Koch / Prof. Dr. Martin Skutella
    Project members: -
    Duration: -
    Status: running
    Located at: Konrad-Zuse-Zentrum für Informationstechnik Berlin

    Description

    Utility and infrastructure networks are at the heart of our daily life and we are taking their proper working for granted. To provide this service, network operators face difficult planning and operational problems. The complexity of the considered optimization problems increases for several reasons, for instance because geographically bigger networks are considered or the detail level is increased. For large networks, providing globally optimal solutions or at least good bounds for assessing solution quality is still a big challenge. This project addresses this challenge for so-called potential-driven nonlinear network flow problems that are a key model for infrastructure networks for fluids, e.g. water and gas. These problems feature a so-called potential for each node, and the flow on an arc is related to the difference of the potential of its end nodes. In particular, flow is always directed from higher to lower potential, i.e. the potentials induce an acylic orientation of the arcs. This observation is the motivation for this project: We study network flow problems with the additional requirement of acyclic flows: If each network arc is oriented in the direction of flow over this arc, then there is no directed cycle in the resulting network. This is an interesting combinatorial structure that arises from nonconvex nonlinear constraints and thus links combinatorial and continuous optimization. The aim of this project is to develop algorithmic techniques to exploit this structure to improve global optimization methods for large-scale nonlinear flow problems.

  • MI-AP10

    Centralized Respository for Test Data

    Prof. Dr. Thorsten Koch

    Project heads: Prof. Dr. Thorsten Koch
    Project members: -
    Duration: 01.10.2014 - 30.06.2018
    Status: running
    Located at: Konrad-Zuse-Zentrum für Informationstechnik Berlin

    Description

    The subproject Z02 aims for a central database of realistic gas network data in standardized formats, and providing interfaces to allow an easy access to the data. This common data standard and common pool of test data drive the workflow and cooperation of all subprojects. A gas network is described by many parameters. Experiences show that it is a very hard task to generate realistic data for gas networks with no access to real data of existing networks.This subproject cooperates with the biggest German network operator, Open Grid Europe GmbH, to compile test data from real gas network data. The generated test data will extend the existing GasLib library for stationary networks. This database relieves other subprojects from generating their own test data, and provides common test cases for them. So, different subprojects can compare their results more easily, since they use the same underlying data. One focus of the subproject Z02 is to standardize the data formats used, and to provide interfaces to them.This interfaces ease the data access for others. The usage of the same data structure throughout the different subprojects leads to more compatible programs and an easier cooperation. The overall goal of the subproject Z02 is to compile a selection of data sets, which can be used to run different demonstration scenarios. The data sets and their descriptions will be published, such that transparency and reproducibility of the results are assured.

    http://trr154.fau.de/index.php/en/subprojects/z02e